Intensive fish farming and the evolution of pathogen virulence: the case of columnaris disease in Finland
Ecological changes affect pathogen epidemiology and evolution and may trigger the emergence of novel diseases. Aquaculture radically alters the ecology of fish and their pathogens. Here we show an increase in the occurrence of the bacterial fish disease Flavobacterium columnare in salmon fingerlings...
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ftpubmed:oai:pubmedcentral.nih.gov:2842694 2023-05-15T17:42:39+02:00 Intensive fish farming and the evolution of pathogen virulence: the case of columnaris disease in Finland Pulkkinen, K. Suomalainen, L.-R. Read, A. F. Ebert, D. Rintamäki, P. Valtonen, E. T. 2010-02-22 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842694 http://www.ncbi.nlm.nih.gov/pubmed/19864284 https://doi.org/10.1098/rspb.2009.1659 en eng The Royal Society http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842694 http://www.ncbi.nlm.nih.gov/pubmed/19864284 http://dx.doi.org/10.1098/rspb.2009.1659 © 2009 The Royal Society Research articles Text 2010 ftpubmed https://doi.org/10.1098/rspb.2009.1659 2013-09-02T22:45:54Z Ecological changes affect pathogen epidemiology and evolution and may trigger the emergence of novel diseases. Aquaculture radically alters the ecology of fish and their pathogens. Here we show an increase in the occurrence of the bacterial fish disease Flavobacterium columnare in salmon fingerlings at a fish farm in northern Finland over 23 years. We hypothesize that this emergence was owing to evolutionary changes in bacterial virulence. We base this argument on several observations. First, the emergence was associated with increased severity of symptoms. Second, F. columnare strains vary in virulence, with more lethal strains inducing more severe symptoms prior to death. Third, more virulent strains have greater infectivity, higher tissue-degrading capacity and higher growth rates. Fourth, pathogen strains co-occur, so that strains compete. Fifth, F. columnare can transmit efficiently from dead fish, and maintain infectivity in sterilized water for months, strongly reducing the fitness cost of host death likely experienced by the pathogen in nature. Moreover, this saprophytic infectiousness means that chemotherapy strongly select for strains that rapidly kill their hosts: dead fish remain infectious; treated fish do not. Finally, high stocking densities of homogeneous subsets of fish greatly enhance transmission opportunities. We suggest that fish farms provide an environment that promotes the circulation of more virulent strains of F. columnare. This effect is intensified by the recent increases in summer water temperature. More generally, we predict that intensive fish farming will lead to the evolution of more virulent pathogens. Text Northern Finland PubMed Central (PMC) Proceedings of the Royal Society B: Biological Sciences 277 1681 593 600 |
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Research articles |
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Research articles Pulkkinen, K. Suomalainen, L.-R. Read, A. F. Ebert, D. Rintamäki, P. Valtonen, E. T. Intensive fish farming and the evolution of pathogen virulence: the case of columnaris disease in Finland |
topic_facet |
Research articles |
description |
Ecological changes affect pathogen epidemiology and evolution and may trigger the emergence of novel diseases. Aquaculture radically alters the ecology of fish and their pathogens. Here we show an increase in the occurrence of the bacterial fish disease Flavobacterium columnare in salmon fingerlings at a fish farm in northern Finland over 23 years. We hypothesize that this emergence was owing to evolutionary changes in bacterial virulence. We base this argument on several observations. First, the emergence was associated with increased severity of symptoms. Second, F. columnare strains vary in virulence, with more lethal strains inducing more severe symptoms prior to death. Third, more virulent strains have greater infectivity, higher tissue-degrading capacity and higher growth rates. Fourth, pathogen strains co-occur, so that strains compete. Fifth, F. columnare can transmit efficiently from dead fish, and maintain infectivity in sterilized water for months, strongly reducing the fitness cost of host death likely experienced by the pathogen in nature. Moreover, this saprophytic infectiousness means that chemotherapy strongly select for strains that rapidly kill their hosts: dead fish remain infectious; treated fish do not. Finally, high stocking densities of homogeneous subsets of fish greatly enhance transmission opportunities. We suggest that fish farms provide an environment that promotes the circulation of more virulent strains of F. columnare. This effect is intensified by the recent increases in summer water temperature. More generally, we predict that intensive fish farming will lead to the evolution of more virulent pathogens. |
format |
Text |
author |
Pulkkinen, K. Suomalainen, L.-R. Read, A. F. Ebert, D. Rintamäki, P. Valtonen, E. T. |
author_facet |
Pulkkinen, K. Suomalainen, L.-R. Read, A. F. Ebert, D. Rintamäki, P. Valtonen, E. T. |
author_sort |
Pulkkinen, K. |
title |
Intensive fish farming and the evolution of pathogen virulence: the case of columnaris disease in Finland |
title_short |
Intensive fish farming and the evolution of pathogen virulence: the case of columnaris disease in Finland |
title_full |
Intensive fish farming and the evolution of pathogen virulence: the case of columnaris disease in Finland |
title_fullStr |
Intensive fish farming and the evolution of pathogen virulence: the case of columnaris disease in Finland |
title_full_unstemmed |
Intensive fish farming and the evolution of pathogen virulence: the case of columnaris disease in Finland |
title_sort |
intensive fish farming and the evolution of pathogen virulence: the case of columnaris disease in finland |
publisher |
The Royal Society |
publishDate |
2010 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842694 http://www.ncbi.nlm.nih.gov/pubmed/19864284 https://doi.org/10.1098/rspb.2009.1659 |
genre |
Northern Finland |
genre_facet |
Northern Finland |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842694 http://www.ncbi.nlm.nih.gov/pubmed/19864284 http://dx.doi.org/10.1098/rspb.2009.1659 |
op_rights |
© 2009 The Royal Society |
op_doi |
https://doi.org/10.1098/rspb.2009.1659 |
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Proceedings of the Royal Society B: Biological Sciences |
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277 |
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1681 |
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593 |
op_container_end_page |
600 |
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